Drug-resistance patterns of clinical isolates of Pseudomonas aeruginosa with reference to their lipopolysaccharide compositions.

Fifty-nine strains of Pseudomonas aeruginosa, isolated from blood, urine, pus, sputum and feces, were divided into three groups on the basis of differences in their LPS composition, in long- and short-LPS strains and in LPS-deficient strains. The long-LPS strains were far more frequently isolated among blood, urine and fecal specimens than in the remainder, and the frequency of LPS-deficient strains was higher in sputum specimens than in the remainder. The drug resistance patterns of the three LPS-type strains to six different kinds of anti-pseudomonal drugs, including gentamicin, differed significantly.